Prophylactic and therapeutic agents have long been delivered to patients using various conventional routes of administration, such as topical, oral, intravenous, parenteral, and the like. Once administered to the patient by the selected route, the delivery of the agent to the tissue of interest and its beneficial interaction with the tissue is largely dependent on its inherent physicochemical factors, but may have been facilitated by, for example, selected components of the delivery composition such as carriers, adjuvants, buffers and excipients, and the like.
More recently, the application of electrical fields has been shown to enhance the movement and uptake of macromolecules in living tissue. Application of such electrical fields in tissue relative to the administration of a prophylactic or therapeutic agent can have desirable effects on the tissue and/or the agent to be delivered. Specifically, techniques such as electroporation and iontophoresis have been utilized to enhance the delivery and/or uptake of a variety of agents in tissue. Such agents include pharmaceuticals, proteins, antibodies, and nucleic acids. Potential clinical applications of such techniques include the delivery of chemotherapeutic drugs and/or therapeutic genes in tumors, the delivery of DNA vaccines for prophylactic and therapeutic immunization, and the delivery of nucleic acid sequences encoding therapeutic proteins.
Many devices have been described for the application of electrical fields in tissue for the purpose of enhancing agent delivery. The vast majority of these have focused on a means for effective application of the electrical fields within a target region of tissue. A variety of surface and penetrating electrode systems have been developed for generating the desired electrophysiological effects.
In spite of the promise associated with electrically mediated agent delivery and the potential clinical applications of these techniques, progress has been hampered by the lack of an effective means to achieve the overall objective of efficient and reliable agent delivery using these techniques. Significant shortcomings of current systems include a complex application procedure, unwieldy device design, potential hazards for the user and patient and the inability to provide a cost effective means for administration.
Given that safe, effective, consistent, and cost effective means for the administration of therapeutic agents are highly desirable, the development of improved application systems is well warranted. Such development should include a means for minimizing operator-associated variability and ensuring the safety of the user and the patient while providing for accommodating the differences in patient characteristics likely to be encountered during widespread clinical application of electrically mediated agent delivery.